Improvement in the steam-engine



UNITED STATES PATENT OFFICE.

ALEXANDER CONNISON, OF .NEI/VARI@ NEW JERSEY.

IMPROVEMENT IN THE STEAM-ENGINE.

Specification forming part of Letters Patent No. 2,872, dated December5, 184?.

To aZZ whom, it may concern,.-

Be it known that I, ALEXANDER CoNNIsoN, of the city of Newark, in thecounty of Essex and State of New Jersey, have invented a new and usefulimprovement in the manner of cornbining, arranging, and operating thepistons and cylinder of a steam-engine, and likewise an improved mannerof comstrncting and aranging a rotary valve adapted thereto; and I dohereby declare that the following is a full and exact descriptionthereof.

vIn my steam-engine I placethe cylinder upon slides, so that it may bemade to vibrate back and forth or up and down, as the case may be. Itis,however, in general intended to be placed horizontally. To thiscylinder I adapt two pistons, the pistonrod of one of them beingtubular, so as to allow the solid rod of the second piston to passthrough it, a stuffing-box being used for the purpose of causing thelatter piston to slide through the former steam-tight. For regulatingthe motion ofthe cylinder and of the pistons I use a threethrow crank,which is so constructed that the three wrists or operating parts ot'said crank shall standat an angle of one hundred and twenty degrees witheach other, and therefore divide the circle of their revolution intothree equal parts. The crank that is to cause the cylinder to vibratemay be double, so as to employ two connecting-rods attached on oppositesides of the cylinder. The crank carrying the hollow piston-rod Isometimes likewise make double,so as to have two connecting-rodsattached to its slide or cross-head, the object in these cases being tosecure steadiness of motion. By this arrangement of two pistons in onecylinder the chamber or interior of the cylinder will be divided intothree compartments or chambers, within which the steam is to operate,instead of into two, as in the ordi- I nary steam-engine, and into eachof these com-- partments the steam must be admitted through suitablevalves and passages and must, in like manner, be discharged therefromwhen its action is to cease. The valves used for these purposes may beconstructed in a variety of ways. They may, for eXample,-be made in theform of revolving, sliding, or other valves, as may be' preferred by theconstructor; but I do not intend to limit myself in this particular, mymain improvement consisting in the so constructing of my engine as thatthere shall be three chambers formed within the cylinder, in whichchambers the steam is to operate, its operation being governed by athree-throw crank of the kind above noticed, and by means of which theaction of the steam upon the crankshaft will be such as to avoid theinfluence of what are denominated dead-points,77 the action of theengine being thereby nearly equalized without its being necessary toemploy a fly wheel to effect such equalization, although, as abovenoticed, steanrvalves of different kinds may be used with my engine. Ihave, however, invented a rotary valve, the respective parts of whichare so arranged as to adapt it in an especial manner thereto, and whichwill be presently described.

In the accompanying drawings, Figure l is a top, and Fig. 2 a side, viewof my engine, supposing the cylinder to be placed horizontally. It may,however, be placed vertically or obliquely when these positions are fromany cause preferred.

The cylinder is represented as transparent, for the purpose ofshowingthe pistons within it. A

A A is the cylinder, which has within it the two pistonsB and C, eacho-f which has its appropriate piston-rod.

D D is the piston-rol of the piston C, and

E E that of the piston B. vThis latter' rod is tubular, the solid rod Dpassing through it, there being a stufiing-box atF to cause the rod D towork steam-tight. The tubular rod E also works through a stuffing-box atG in the head of the cylinder H in the usual manner. I is the oppositehead of the cylinder.

The pistons B and C are made to vibrate within the cylinder by means ofcranks, and the cylinder itself I also, in general, make to vibrate, thevibrations being effected in a manner to be now described.

J J is a crank-shaft, upon which I, in preference, form four andsometimes tive cranks, but in such manner as that it shall stillconstitute a three-throw crank, two of the cranksnamely, those whichgive motion to the cylinder--standing in the same direction and beingdouble for the sole purpose of giving steadiness to the vibration byconnecting their rods or shackles to opposite sides of the cylinder, andthe crank which is to vibrate the piston B, I sometimes make double.

K K are the two cranks, which vibrate the ranged for that purpose.

cylinder, L L being the two connecting-rods leading from them to thesides thereof and embracing the pins M M, attached thereto. The cylinderis sustained and guided by the slide or guide-pins N N, which pass intoslots or guidegrooves O O in the frame l? P of the engine, or bymeans ofany other suitable supports or slides.

Q and R are two connecting rods or shackles, which connect thepiston-rods D and E with the two other cranks on the shaft J J, whichcranks are shown at S and T, Fig. 2.

The cranks K, S, and T st-and at an angle of one hundred and twenty'degrees from each other, dividing the circle of their revolution intothree equal parts. They are of equal length, the two pistons and thecylinder each vibrating to the same distance.

U U is a cross-head, to which the piston-rod D is attached, and which isembraced by the shackle Q. This crosshead is shown separately in Fig. 3.Through an eye, V, in it the shackle R passes, said shackle embracingthe cross-head W, to which the tubular piston-rod E is attached.

X and Y are the slide-pins or ends of the cross-heads U and W,respectively, these ends being received into and guided by the slot orgroove O O.

From the abovedescribed arrangement of the pistons, the cylinder, andthethree-throw crank, (the piston-rods being made of the proper length,)the pistons B and C will, when the engine is in motion, be madealternately to approach toward and to recede from each other. The pistonB and the head H will also in like manner bc made to approach and torecede, and so will the piston C and the head I. The two pistons andheads will divide the cylinder into three chambers or compartments, intoeach of which the steam is to be admitted, and is allowed to operateexpansively in them, after doing vwhich it is to escape througheduction-openings suitably ar- The admission of steam between the twopistons is to commence at the instant of their nearest approach to eachother, and this must be continued during that portion of the stroke dueto its direct admission, when it is to be cut off and allowed to actexpansively during the remainder of the stroke. When the pistons haveapproached each other, and the steam which is to be admitted betweenthem is about to be let on, they will not at first recede sensibly fromeach other, nor will they remain at rest, but will travel on together toa certain distance and will then begin to recede. It will be evident,therefore, that the steam cannot be let on at the point of junctionbetween the two pistons vor at any determinate point between them for asufficient space of time unless some special provision be made for thatpurpose, and this I accomplish in the following manner. Y

Z Z are notches or cavities made in the peripheries of eachvof thepistons, which cavi-V ties will coincide when the pistons are broughttogether, and are to be immediately under the induction-opening. Toallow of the formation of these cavities, I give a greater width orthickness to the pistons on the sides which are toward each other thanon their reverse sides, and their packing is consequently not in thecenters of their peripheries. This increased width should be no greaterthan is necessary for the admission of steam, and its proper extent canbe readily ascertained.

The dotted lines at Z Z, Fig. 2, show the form in which the cavities inthe pistons may be made, although this form is not essential. A likeeffect would be produced by beveling the edges of the two pistons allround; but this would cause a waste of steam. The steam is in likemanner to be let into the compartment A when the piston B has made itsnearest approach to the head H, and into the compartment A when thepiston C is nearly in contact with the head I. Theinduction of steaminto the three chambers will take place at equal intervals, as will alsoits eduction or escape therefrom. It may of course be cut o' at any partof the stroke; but I am of opinion that as a general rule the cuttingoff at oneeighth of the length of each of the compartments, reckoningsaid length at the point-s where the twopistons or the respectivepistons and the heads of the cylinder are at their greatest distancefrom each other, will be found to be the best mode of procedure,employing the steam with the greatest economy. I will now proceed todescribe my improved rotary or revolving valve, and the manner in whichI apply it to my vibrating cylinder.

Fig. 4 is a sectional view of a part of the exterior of mysteam-cylinder, together withl a portion of the apparatus constitutingthe rotary valve and the seat thereon. Fig. 5 is a similar view of theinner portion of a part of the steam cylinder, valve seat, andsteamways, these sections being made through the axis of the cylinderlongitudinally and through the-middle of the valve-seat. Fig. 6 is atransverse section through the line c b of Fig. 4, the respective partsof the valve being shown in place. Fig. 7 is a view of the revolvingvalve, its stationary;cap, and a fly-wheel attached to its shaft, asseen on its inner side.

A A is the steam-cylinder.

B B is the valve seat or box.

C is the steam-pipe, leading from the boiler to the valve-box.

D isa stnffmgbox, through which the pipe C' slides steam-tight,thetubular space represented in the lower part of the valve-box by thedotted lines E) being of sufficient depth to allow of the passing in andont of the steampipe C under the requisite vibration of thecylinder.This tubular space leads into the valve-box through an opening at F.

The three openings G in the valve box lead to the three steamways H H H,Fig. 5, which constitute the induction and eduction passages, the ways Hand H leading to the ends of the cylinder and H to the chamber betweenthe two pistons. To regulate the size of the openings G', I placea disk(seen in section at 1') in the bottom of the box B', said disk havingthree openings through it corre` sponding with the openings G', and thisdisk constitutes the proper seat of the revolving The object of it is toobtain the means of regulating the size of the openings G', and for thispurpose the disk is made to revolve to a small distance by means of atangent screw, J', acting on its'periphery, and thus opening or closingthe apertures G' to any desi red extent.

K is the rotary valve,which is made fast to the axle L', said axlehaving on it also the iiywheel M. The valve K' is ground to fit closelyon the seat I'. The induction-opening through this valve is shown at N'.The length of the opening will determine the point at which the steamshall be cut off. The space O' O' between the cap-plate P' and the valveK' constitutes the steam box or chamber, which receives the steam fromthe induction-opening F'. The cavity Q' in the inner face of the valveK' covers two of thev openings G' and effects the eduction or escape ofthe steam in the same way as in the ordinary slide-valve. There is anopening, R', through the center of the valve-seat- I' and into thecavity R' of the box B', which cavity leads to the opening S', Ihroughwhich the waste steam is to escape. The axle or shaft L' fits closely inits Vbearings in the cap I" and the box B', and may be provided withstuffing-boxes. The valve K may be made to revolve by means of a crankand shackle-bar.

T' is a crank-pin on the ily-wheelM', which has the same throw or radiuswith the cranks that vibrate the cylinder and pistons. The shackle orconnecting rod, one end of which embraces the crank-pin T', is at itsother end connected with a j oint-pin,which is attached to theframework, and is stationary, the vibration of the cylinder giving thenecessary throw to the crank-pin T,and causing the valve to revolve.

In order to reverse the motion ofthe engine, I make my valve double inall itsparts-that is to say, the box B' and all its appurtenances arerepeated on the side of the cylinder, (not shown in the drawings,)thesteam-ways H being com mon to both. Ihe shafts L' of each of thesevalves are coupled together by a feather or otherwise, and by shiftingthe induction from one of these valves to the other the motion of theengine will be reversed in a manner well known.

It 'will be manifest that the cylinder-heads fitted into thecylinder,and lare packed as pistons, and they are made to vibratesimultaneously to the same distance-and in the same direction,just asthe two heads H and I are made to vibrate with the cylinder in thewithin-described engine. This vibration of the piston-heads, everymachinist will perceive, may be effected by connecting the shackles orrods L L, Fig. l, by means of cross-heads or otherwise, with the twoheads so litted-as pistons into a stationary cylinder. Under thismodification of my machine a rotary valve similar to that hereindescribed may be employed for the induction and eduction of the steamwith no other change in its arrangement than that which wouldnecessarily result from the cylinder being stationary; but valves ofother kinds may be employed.' After due consideration, however, I havegiven the preference to the plan of making the cylinder itself tovibrate, as being less complex, attended with less friction and lessloss of steam, than with the vibrating heads, as a portion of steam willbe condensed when the heads are made to vibrate by the cooling influenceof the atmosphere to which both surfaces of the cylinder ends will beexposed duringa part of every stroke.

Having thus fully described the nature of my invention and set forth themanner in which the same is carried into operation, I do hereby declarethat I do not claim the employment of two pistons within one cylinder,this not being in itself new, nor do Iclaim the use of a tubularpiston-rod admitting another piston-rod to work through it, these havingbeen previously used, but not under an arrangement and combinationsimilar to that adopted by me.

l. The manner herein described of combining the two pistons and thecylinder with a threethrow crank, the acting portions of which are atthe distance of one hundred and twenty degrees apart, in such manner asthat the two pistons and the cylinder shall be made to vibrate to equaldistances, and so as to allow of the introduction of steam into threecompartments or chambers within the cylinder to operate therein for thepurpose and in the manner set forth. I also claim as a modification ofthis plan the causing of the piston-heads to vibrate within a stationarycylinder,said heads being fit-ted to the cylinder in the manner ofpistons and their vibrations being simultaneous, such heads traversingwithout the cylinder in the same manner in which they would traversewith it under the first-described modication and effecting the samepurpose as the vibration of the heads with the cylinder, and by meanssubstantially the same, there being in either case three distinctmotions-namely, that of the two cylinder-heads and 'those of the twopistons-produced by a three throw crank, constructed and proportioned asset forth.

2. The manner in which I have combined and arranged the respective partsof my rotary valve, as herein described. I do not claim to be the firstinventor of a rotary valve; but I do claim the combining of the tangentscrew, the valve-seat, the openings through that seat and through thevalve-box, so as to be capable of adjustment and to cause them tooperate as set forth. I claim the manner of causing this valve torevolve by means of a shackle -bar held on a stationary j0int-pin at oneend and embracing a crank-pin on the other, by which motion shall begiven to the valve-shaft.

3. The manner of letting the steam on betweenthe two pistons by means ofa device substantially the same with that represented at Z Z in theaccompanying drawings, and described in the specification, by whichmeans the introduction of steam between the two pistons may be continuedduring the time required for that purpose.

I have thus made known what I consider to be the best manner ofconstructing, arranging, and operating the respective parts of myengine; but I do not intend by this description to limit or confinemyself to the precise forms or proportions herein given, but to Varythese as I may think proper, while I attain the same end by meanssubstantially the same.

ALEXANDER CONNISON.

'Vitnesses:

THos. P. Jonas, P. K. MoRsELL.

